1. Field
The following description relates generally to wireless communications, and more particularly to employing a merger of maximal ratio combining (MRC) and interference nulling to weight received signals from multiple receive antennas and combine the weighted, received signals in a wireless communication environment.
2. Background
Wireless communication systems are widely deployed to provide various types of communication content such as, for example, voice, data, and so on. Typical wireless communication systems can be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, . . . ). Examples of such multiple-access systems can include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), and/or multi-carrier wireless specifications such as evolution data optimized (EV-DO), one or more revisions thereof, etc.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple mobile devices. Each mobile device can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations can be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth. In addition, mobile devices can communicate with other mobile devices (and/or base stations with other base stations) in peer-to-peer wireless network configurations.
MIMO systems commonly employ multiple (NT) transmit antennas and multiple (NR) receive antennas for data transmission. A MIMO channel formed by the NT transmit and NR receive antennas can be decomposed into NS independent channels, which can be referred to as spatial channels, where NS≦{NT, NR}. Each of the NS independent channels corresponds to a dimension. Moreover, MIMO systems can provide improved performance (e.g., increased spectral efficiency, higher throughput and/or greater reliability) if the additional dimensionalities created by the multiple transmit and receive antennas are utilized.
A conventional wireless communication apparatus (e.g., base station, mobile device, . . . ) typically includes a receiver that receives signal(s) from, for instance, one or more receive antennas, and performs actions thereon (e.g. filters, amplifies, downconverts, . . . ) the received signal(s). Oftentimes, the receiver can obtain multiple signals from a plurality of receive antennas, and the multiple signals can be combined to realize diversity and power gains due to independent channel and noise processes on different receive paths. Conventional techniques for merging the multiple signals, however, typically yield different levels of performance gains relative to each other when noises in the receive paths are correlated as compared to when noises in the receive paths are uncorrelated.